Panic with no arguments

[tylerhawkes]

I just upgraded to v0.28 and all that cargo tree does now is panic. It doesn't matter if I run it with or without arguments.

thread 'main' panicked at 'called `Result::unwrap()` on an `Err` value: ()', src/libcore/result.rs:1165:5
stack backtrace:
   0:        0x101fa01a5 - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::h415ddd0ba88caaaf
   1:        0x101fc6b80 - core::fmt::write::h3335552e2df81c1d
   2:        0x101f9bb8b - std::io::Write::write_fmt::he6837371b9a45188
   3:        0x101fa3253 - std::panicking::default_hook::{{closure}}::h708e66cfeb0483ba
   4:        0x101fa2f5a - std::panicking::default_hook::h39ea8ddf674c04ec
   5:        0x101fa391b - std::panicking::rust_panic_with_hook::h9db77b22c2255a16
   6:        0x101fa34a9 - std::panicking::continue_panic_fmt::h2dfa3a5b90265361
   7:        0x101fa33f9 - rust_begin_unwind
   8:        0x101ffee5c - core::panicking::panic_fmt::hec1ee47b7e17dca5
   9:        0x101ffef39 - core::result::unwrap_failed::hc206b0330c60884a
  10:        0x101c8a357 - cargo::util::canonical_url::CanonicalUrl::new::h4f284ad14d8ab2aa
  11:        0x101d004d2 - cargo::core::source::source_id::SourceId::new::hd2f02e642b53a244
  12:        0x101c9bf74 - cargo::util::toml::DetailedTomlDependency::to_dependency::hfc3bd042878100d4
  13:        0x101c9aed2 - cargo::util::toml::TomlDependency::to_dependency::hb51ec1e031d6997e
  14:        0x101c99a87 - cargo::util::toml::TomlManifest::to_real_manifest::process_dependencies::h62aab64f24ff9efd
  15:        0x101c95e1d - cargo::util::toml::TomlManifest::to_real_manifest::h9882a1e8a9f71e1b
  16:        0x101c8fc33 - cargo::util::toml::read_manifest::h62bc24cf28e896b3
  17:        0x101b5ed74 - cargo::core::workspace::Packages::load::h65ce78f1ea455081
  18:        0x101b5b260 - cargo::core::workspace::Workspace::find_root::h55bbaac9bb1332e1
  19:        0x101b58b2a - cargo::core::workspace::Workspace::new::h91e0ac88a904a5a4
  20:        0x101adf5d6 - cargo_tree::real_main::h7d8a98ad3f9d469f
  21:        0x101adea17 - cargo_tree::main::hcdbcb77e31dba704
  22:        0x101ad2986 - std::rt::lang_start::{{closure}}::h736238767a8fa0f9
  23:        0x101fa3378 - std::panicking::try::do_call::hd5a3af8d00c06681
  24:        0x101fab2cf - __rust_maybe_catch_panic
  25:        0x101fa3d6e - std::rt::lang_start_internal::haa52aabac43378ff
  26:        0x101ae4699 - main

I have couple hundred dependencies and just ran cargo update so everything resolves.